Blddemo command in Visual Studio

I'm a beginner. I'm using Visual Studio 2005 and getting trained in building WinCE 6.0 OS Image. I cloned an existing BSP and was trying blddemo related commands on it. One among them was "blddemo". I actually didn't let the build to complete fully. Closed the command window immediately after 1 min (as I was just taking notes). I didn't know that it is the dangerous "Build and Sysgen"! I came to know it only now, after reading a blog (guruce blog - what-to-build-when). What should I do now? How do I check if the previous binaries of QFE has lost? Kindly guide me.